1. Field of the Invention
The present invention relates to a focus detecting apparatus and an imaging apparatus.
2. Related Background of the Invention
There is known a camera system capable of correcting a defocus amount in accordance with a spherical aberration of an imaging optical system and detecting an optimum focusing position (Japanese Unexamined Patent Publication (Kokai) No. 62-227108). The camera system has a lens barrel in which spherical aberration correcting data values corresponding respectively to two F values are stored. Then, these two spherical aberration correcting data values are read out into a camera body mounted with the lens barrel. The camera body has a focus detecting optical system with unique full aperture F value, and after determining an optimum weighting coefficient according to the full aperture F value, each of the two spherical aberration correction data values is multiplied by the weighting coefficient. In this way, there is calculated a spherical aberration correcting amount optimum for the focus detecting optical system.
However, the spherical aberration correcting amount obtained in the above-mentioned prior art camera system is calculated equally, and differs from a correcting amount for the focus detecting optical system, unique to each lens barrel.